Photograph of Mickey's Diner taken on July 16, 1975 by Steve Plattner.

Mickey Crimmons and Bert Mattson opened Mickey's Diner, located at 36 West Seventh Street in downtown St. Paul, in 1939. Such diners had gained popularity early in the twentieth century as inexpensive, often all-night, eateries. Built to resemble a rail car, Mickey's was particularly notable for its unique look. Its unusual architecture made it a local landmark, and earned it a place on the National Register of Historic Places.

Fifty feet long and ten feet wide, Mickey's has distinctive red and yellow porcelain-enameled steel panels and Art Deco-style lettering on the exterior. A row of ten train-style windows graces the front. The building was prefabricated in 1937 by the Jerry O'Mahony Diner Company in Elizabeth, New Jersey, to resemble a dining car on a passenger train. Then, it was shipped by rail to St. Paul. The interior—a setting for scenes in a handful of movies—features floor-mounted round stools along a well-worn counter.

Mickey's Diner has been operating as a family-owned business since the year it opened. On February 24th, 1983, it was added to the National Register of Historic Places.

Besides its architecture, Mickey's is known for its all-day (and all-night) breakfast menu. The menu features such staples as eggs, pancakes, and hash browns. It also includes Mickey's homemade mulligan stew, hamburgers, and ice-cream floats, shakes, and malts. The diner's website includes Mickey's schedule ("Open 24 hours a day, 365 days a year") and its "House Rules" ("No smoking, no checks, no take out").

Mickey's is famous beyond Minnesota. It was named one of America's Top Ten Diners by Jane and Michael Stern in Gourmet magazine. It also has been featured on travel and food television series like Unwrapped, Roker on the Road, Rachel Ray's Tasty Travels, and Alton Brown's Feasting on Asphalt. The unusual diner has been showcased in magazines such as Smithsonian, National Geographic, and Sports Illustrated.

The diner also has appeared in movies that include the Mighty Ducks series of the 1990s and Jingle All the Way (1996). The opening and closing scenes of Robert Altman's A Prairie Home Companion (2006) were both shot at Mickey's.

On September 3, 2008, during the Republican National Convention in St. Paul, photographs of the diner appeared in local and national newspapers for a different reason. Police confronted about two hundred protesters in front of Mickey's Diner. They dispersed them with tear gas, pepper spray, and flash grenades.